Periodic circuit breaker with a liquid conductor particularly for contact current changers



y 1948- M. H. w. WIDAKQWICH 2,

PERIODIC CIRCUIT BREAKER WITH A LIQUID CONDUCTOR, PARTICULARLY FORCONTACT CURRENT CHARGERS Filed April 6, 1945 luvaNw-oa M.H. \N.WiDAKuwicH Patented July 6, 1948 PERIODIC CIRCUIT BREAKER WITH A LIQ- UIDCONDUCTOR PARTICULARLY -FOR CONTACT CURRENT CHANGERS Marius Hugo WilhelmWidakowlch, Stocksund, Sweden Application April 6, 1945, Serial No.588,914 In Sweden April 6, 1944 5 Claims. (Cl. 20032) The presentinvention relates to a periodic circuit breaker which is particularlyintended to be used as a contact current changer for the conversion ofalternating current into direct current, or vice versa, and wherein anelectrically conducting liquid, preferably mercury, is employed as aconductor, while contact members are used for periodic closing andbreaking of one or more circuits. The invention refers particularly tosuch circuit breakersof said type which consist of two receptaclesholding the contact liquid and communicating with each other, saidreceptacles being arranged concentrically within one another, and 'oneof which is stationary and the other rotatably mounted, the' contactliquid being adapted to circulate through the receptacles in a manner toform a number of jets ejected from the one receptacle, said jetscooperating with peripheral contacts in the other receptacle. Theinvention is principally distinguished by the feature that the rotaryreceptacle is formed as a rotary pump, preferably as a centrifugal pump,to circulate the contact liquid through the two receptacles. By thismeans a compact constructionoi the circuit breaker is obtained, inasmuchas the circulation pump, which is otherwise necessary, is now dispensedwith. Thearrangement also involves the advantage that the circulationsystem may be housed,-together. with all of the contacts, within aclosed vessel which is preferably constituted by the one receptacle,which is then preferably arranged to be stationary, whereas the otherreceptacle is rotatably mounted within said first-mentioned receptacleand adapted to be driven from an external source of power by means of arotating magnetic field. .If desired, the outer vessel may then behermetically closed, and the circuit breaker may be adapted to operatein, vacuum or in an atmosphere .ot a neutral gas sothat the contactbreaking takes place without sparking, as far as possible.

The invention will be explained more closely with reference to theaccompanying drawing,

2 drical portion 3 and a bottom portion provided with a downwardlyextended central portion 4 and a draining hole closed by means of athreaded stopper 5. The two receptacles communicate with one anotherthrough a central hole i in the lower portion of the inner receptacle 2.The receptacles are filled with mercury which. when the apparatus isinoperative, takes about the level indicated by the dashed line I. Theinner receptacle is mounted by means of ball bearings 8, 9 on a centraljournal pin l0 screwed fast into a cover I I of glass or othernon-magnetic and electrically non-conducting material. The cover It isrigidly connected with the receptacle I and tightens against a flange l2extending around the upper edge thereof. The ball bearings 8, l areenclosed within a cap I: for'ming'a cylindrical extension of a cover 14covering the upper part of the inner receptacle while being rigidlyunited with the receptacle. The latter cover consists of magneticmaterial, preferably iron, and is provided with a number of pole piecesii, the upper surfaces of which are located immediately underneath thecover I I. Rigidly arranged on a journal I6 coaxial with the pin l0 andsituated above the cover H is a yoke I! of iron, said yoke supporting anumber of magnet cores corresponding to the pole pieces l5, said coresbeing provided with magnet windings IS. The parts M, l5, l1 and-l8 thusform a magnetic circuit through which the torque of the motor may betransmitted to the inner receptacle 2, which then rotates at the speedof the motor shaft. The pole pieces are surrounded by rings 20 of copperor other electrically conducting material said rings "being adapted inknown manner to facilitate-the starting.

The inner receptacle 2, is of a downwardly tapering, substantiallyconical shape, and is provided on the inside thereof with a number ofradially disposed partitions Zl adapted at therotation to entrain thequantity of mercury" flowing through the receptacle, the rotatingreceptacle then acting as a centrifugal'pump, and the mercury enteringfrom the outer receptacle to the inner one through the opening, 6. Inorder to increase the impelling force acting upon the mercury, the lowerparts of the radial partitions 2| mercury will thus flow up along thewall of the receptacle throughthe action of the centrifugal force, aportion of the mercury then escaping through a number of apertures 22provided in the wall, said apertures opening into ejecting nozzles 23.To ensure the discharge of a sumcient quantity of mercury through saidnozzles. the receptacle is provided on the inside thereof with a pro-Jecting circularly extending edge 23 adapted to catch a portion or themercury. The remainder of the mercury continues along the portion of theconical receptacle wall situated above the nozzles 23 and escapesthrough apertures 23 provided in the upper portion or the wall, thenumber of said apertures equalling that of the nozzles 23 and lying, inthe example shown, in the same axial plane as the latter.

The mercury escaping downwardly through the upper openings 23 isreceived by channels 23 in a number of metallic contact members 21arranged in an insulating manner on the inside of the cylindrical wall 3of the receptacle I, said contact members being electrically connectedwith contact clamps not shown in the drawing to make connection with theexternal circuits. The electric insulation between the contact members21 and. the outer receptacle wall'3 is constituted by a cylinder 28 ofceramic material, for example. The contact members 21 are formed asejecting nozzles for a corresponding number of stationary connectingjets, and are to this end provided with a through passage 29, throughwhich the mercury received in the channel 23 is discharged downwardly inthe form of a compact Jet passing as a single elongated jet through arecess or a free space 33 in the lower portion of the contact member. Tofacilitate the return of the mercury to the common collecting place inthe bottom of the outer receptacle 2, without the Jets then makingcontact with the mercury contained in the receptacle I, there isprovided a screen or channel 3| in the path or the jet, said screen orchannel being adapted to catch the mercury Jet and to cause the mercuryon its passage through the perforation holes to be finely divided andtransferred to the receptacle l in the form of a stream of particles ordrops insulated from one another. The recesses 33 are open inwardly andsituated on a level with the ejecting nozzles 23. The rotatingconnecting Jets discharged from the latter ejecting nozzles willconsequently penetrate into the space 30 so as to make contact with thestationary connectin jet discharged from the channel 29. To preventnon-desirable movements of the quantities of the mercury flowing intothe space 30, there are provided throughholes 32 in the contact piece 21and in the insulating wall 28 opposite the ejecting nozzles 23, throughwhich the horizontal mercury jets may continue into an annular recess 33in the wall 3, said recess opening through passages 34 adjacent to thebottom of the receptacle I, so that the mercury may return this way tothe lower portion of the receptacle. The annular recess 33 and theopenings 32 are so arranged that no direct conducting connection may beproduced between the contact pieces 21 and the outer receptacle I, afterthe horizontal jet has moved during its rotation past the contact pieceso as to break the contact therewith. The mercury quantities returningto the outer receptacle are collected in the downwardly extended centralportion 3, from which the mercury is driven up into the inner receptaclethrough the influence of the centrifugal force, in the manner indicatedhereinbefore. To prevent the mercury in the outer receptacle from beingbrought into rotation by the friction against the inner receptacle,radial partitions 30 may be provided in the outer re ceptacle. Theinflow oi the mercury through the opening 3 may also take place througha tube fixed in the outer receptacle and connected to said opening, saidtube tightening against the wall of the inner receptacle by means of alabyrinth packing or the like.

Provided between the contact pieces 21 and the lass cover H are distancemembers 35, which may be made from metal or from insulating material,and which in a suitable manner confine that space above the channel 28in which the ejecting nozzles 25 are moving.

As will appear from Figure 2, the channels 23 extend, the same as thechannels 23, approximately over the whole length of the contact pieces21, the stationary jets then escaping from the channels 20 obtaining acorresponding width. Since the rotating jets discharged from the nozzles23 are preferably thread-like, the length oi the channel 23 in aperipheral direction will thus determine the length of the contactclosing periods. In the example shown, it is assumed that the nozzles 23and 25 are located opposite each other, contact closing thus takingplace approximately at the same time between the feeding jet dischargedfrom the nozzle 25 and the contact piece 21, on the one hand, and thestationary connecting Jet and the rotating connecting jet dischargedfrom the nozzle 23, on the other hand. After that, the contact ismaintained both ways, until the feeding jet discharged from the nozzle25 moves past the fore edge of an insulating screen 36, which isarranged over the end of the contact piece. The feeding of mercury intothe channels 23 being then interrupted, the contact will now bemaintained only by the rotary connecting jet discharged from the nozzle23. as long as this jet makes contact with the stationary connectingjet. This ensures that contact breaking will always take place betweentwo mercury jets and that, consequently, the breaking of the feeding Jetat the edge of the insulating screen 36 may take place withoutsparking.-

The insulating screens 38 are so arranged as to cover the ends of twoadjacent contact pieces 21, that edge of each individual screen which isremote in the direction of movement then determining the time for theclosing of the current. By changing the position of said edge relativelyto the channel, the length of the contact closing period may be varied.

Theperiodic circuit breaker may be arranged for the control of anydesired number of external circuits by the arrangement of acorresponding number of contact pieces 21 about the inside oi the outerreceptacle. In the example shown, there are provided nine contact piecesof said type.

To prevent the mercury as far as possible from entering the ball bearinghousing". there are provided labyrinth packings 31 between the covers Hand H, the lower pockets in said labyrinth packings then communicatingthrough passages with the interior of the receptacle 2 for the purposeof deflecting mercury. The small quantities of mercury which might stillpenetrateinto the bearing housing l3 are carried off through apertures38 in the bottom of the bearing housing, and filters may then beprovided above said apertures, so that the bearing oil is prevented fromfinding its way out through the apertures. Such means to prevent themercury from penetrating into the bearing housing are believed to besuperfiuous, however, as the bearing housing I3 should permit of beingfilled with mercury, so

that the balls of the bearings are moving in mercury.

In order to prevent the feeding jets from disturbing the collection ofmercury in the channels 26 on account of the velocity of such jets,whereby interruptions might occur in the jets escaping through thechannels 29, it is possible, as shown in Figure 3, to provide a specialdistributing channel 39 between the nozzles 25 and the contact pieces21, the mercury being then first caught by said channel, from which themercury escapes immediately through apertures in the bottom of thechannel, so that the mercury flows down into the channel 26 in a finelydivided state, for instance in the form of line jets or small drops.Said channel 39 may extend continuously about the whole circumference.In this case, the current will be closed and interrupted solely by thecontact between the rotating jet escaping from the nozzle 23 and thestationary let escaping through the channel 29.

I claim;

'1. Periodic circuit breaker with a circulating contact liquid,particularly for contact current changers, characterized in that thecirculation system comprises a stationary outer receptacle and arotating inner receptacle serving as a circulation pump, saidreceptacles being provided with electing nozzles for the contact liquid,so arranged that the contact liquid is divided during its circulationinto a system of rotating jets and a system of stationary jets, therotating jets discharged from the ejecting nozzles of the innerreceptacle being adapted periodically to make contact with thestationary jets discharged from a number of mutually insulated ejectingnozzles in the outer receptacle.

2. Periodic circuit breaker according to claim 1, characterized in thatthe rotary part serving as a circulation pumpis adapted to feed both jetsystems.

3. Periodic circuit breaker according to claim 1, characterized in thatthe feeding of the stationary jets is adapted to take placeintermittently and synchronously with the contact closing betweencorresponding rotating and stationary jets.

4. Periodic circuit breaker according to claim 1, characterized in thatthe feeding of the stationary jets is adapted to take placeintermittently and synchronously with the contact closing between thecorresponding rotation and stationa y jets, means being provided forinterrupting the feeding of contact liquid before the contact betweenthe corresponding stationary and rotatin jets is interrupted.

5. Periodic circuit breaker according to claim 1, comprising stationarychannels for the stationary jets, ejecting nozzles in the innerreceptacle adapted to deliver contact liquid to said stationarychannels, and distributing channels arranged between said ejectingnozzles and the stationary channels and adapted to receive the liquidfrom the ejecting nozzles and to discharge the liquid into thestationary channels in the form of drops so as to maintain the liquidsupplied through the said ejecting nozzles electrically insulated fromthe stationary jets.

MARIUS HUGO WILHEIM WIDAKOWICH.

REFERENCES CITED The following references are of record in the die ofthis patent:

UNITED STATES PATENTS Number Name Date 690,973 Luschka Jan. 14, 1902FOREIGN PATENTS Number Country Date 192,704 Great Britain May 1, 1924676,808 France June 18, 1929

